You can't always get what you want

Sorry, but you can't always get what you want.

This is true in life, you can't always get what you want. When you are an adult you have many factors that limit what you may have. If your friend has a new car, you understand that car is his not yours. When you go to a store, you understand that you cannot afford to buy everything you see or want. It is your job to prepare your child for a realistic future, in which they have to work to earn things.
If your child's behavior has been found to be cause by not being able to get what they want (access to tangibles) flexibility will need to be learned and practiced. It is a great idea to set up a behavior contract to let your child know exactly what is expected of him. The behavior management package on the left of the screen, is an excellent tool.
Example: Johnny wants to drink grape juice but there is no grape juice left so he cries. Let him know his options other than grape juice. Say, "there is no grape juice, you may have apple juice or water." If he chooses apple juice or water go overboard in praising him on his flexibility. If he continues to cry, tell him crying is not one of the choices and repeat his choices again. If you have to repeat more than twice, ignore the crying. When he is thirsty enough, he will drink.

 

Once you have a behavioral plan set up at home, both parents need to follow it and you should let your child's teacher know how you handle different situations so when they occur at school they can be handled in the same manner. The consistency will help your child learn how to make the right choices faster. Some of these behavior suggestions might sound cold or uncaring, but it does your child more harm to not discipline them and not teach them how to make good choices. They already have a disadvantage socially, you need to help them understand how to behave so other children will be able to play with them and enjoy their company.